New Study Reveals Reptiles' Spontaneous Association Between Vision and Hearing
Published:16 Aug.2023 Source:Queen Mary University of London
An international research team from Queen Mary University of London, UK and the Rovereto Civic Museum Foundation, Italy has made a groundbreaking discovery regarding reptiles and their ability to match visual and auditory information. Their study published in Biology Letters from Royal Society showed that reptiles demonstrate spontaneous associations between two different sensory modalities: vision and hearing. Tortoises associated low sounds with large shapes and high pitch sounds with small shapes, even if they had not been trained to do so. These results show how brains are prepared to predict visuo-acoustic correspondences that are likely to occur in the natural world.
To unveil the presence of spontaneous preferences for matching the two dimensions of acoustic pitch (high vs low tone) and visual size (small vs large disk), the team tested land tortoises (Testudo hermanni) in a choice task. After being trained to follow any sound to find a food reward, tortoises were tested for the preference for high and low pitch sounds associated to either small or large shapes. The tortoises consistently chose small disks when presented with high pitch sounds, and large disks when low pitch sounds were presented. The study has helped us understand how the patterns present in the natural environment such as correspondence between size and pitch shape the cognitive abilities of animals.
These findings suggest that crossmodal associations are widespread across species and animal groups, indicating that they may be an organising principle of the vertebrate brain. It is possible that mammals, birds, and reptiles have independently evolved this mechanism, or it may be a predisposed mechanism shared by descent from a common ancestor. Expanding research to a broad range of species is important to understand general principles of the organisation of the brain and evolution of behaviour.